Inclinometer to Determine Orientation of Gauge Installed Off Center Axis of a Tubing String

Abstract

A method and apparatus for estimating an orientation of a downhole device conveyed into a well on a conveyance device is disclosed. The apparatus includes a first sensor and a second sensor placed circumferentially spaced apart on the device to provide measurements relating to a selected downhole parameter. A processor is configured to estimate the orientation of the downhole device using a phase difference between the measurements of the first sensor and the second sensor.

1 . A method of estimating an orientation of a downhole device conveyed into a well, the method comprising:
 producing a first signal and a second signal indicative of a downhole parameter using a first sensor and a second sensor disposed circumferentially apart on the downhole device when the downhole device is conveyed into the well;   estimating a phase difference between the first signal and the second signal; and   estimating the orientation of the downhole device using the estimated phase difference.   
     
     
         2 . The method of  claim 1  further comprising selecting the downhole device from: (i) a gauge carrier, and (ii) a perforating device. 
     
     
         3 . The method of  claim 1 , wherein the device is conveyed into the well using a conveyance device selected from one of: (i) a tubing; and (ii) a wireline. 
     
     
         4 . The method of  claim 1 , wherein estimating the phase difference further comprises applying a correction for a run-in of the downhole device. 
     
     
         5 . The method of  claim 4 , wherein applying the correction further comprises using a well deviation from vertical, a measured depth, a run-in rate and a fluid density of a fluid in the well. 
     
     
         6 . The method of  claim 1 , wherein estimating the phase difference comprises at least one of: (i) applying a Short Term Fourier Transform; and (ii) estimating a quadrature signal of the phase difference between the first signal and the second signal. 
     
     
         7 . The method of  claim 1 , wherein the first sensor and the second sensor are pressure sensors. 
     
     
         8 . The method of  claim 1 , wherein estimating the phase difference between the first signal and the second signal and estimating the orientation of the downhole device comprises using a processor to process the first signal and the second signals. 
     
     
         9 . The method of  claim 8 , wherein the processing of the first signal and the second signal comprises processing the first signal and the second signal at a location selected from a group consisting of: (i) a downhole location; (ii) a surface location; and (iii) partially in the well and partially outside the well. 
     
     
         10 . An apparatus for estimating orientation of a downhole device, the apparatus comprising:
 a first sensor and a second sensor placed circumferentially spaced apart on the downhole device, each sensor configured to provide measurements relating to a selected parameter; and   a processor configured to estimate a phase difference between the measurements of the first sensor and the second sensor and estimate the orientation of the downhole device using the estimated phase difference.   
     
     
         11 . The apparatus of  claim 10  wherein the processor is further configured to estimate the orientation of the downhole device by applying a correction for a run-in of the downhole device. 
     
     
         12 . The apparatus of  claim 11  wherein the processor is further configured to apply the correction using a well deviation from vertical, a measured depth, a run-in rate and a fluid density. 
     
     
         13 . The apparatus of  claim 10  wherein the processor is further configured to estimate the orientation of the downhole device by at least one of: (i) applying a Short Term Fourier Transform, and (ii) estimating a quadrature signal of the phase difference between the first signal and the second signal. 
     
     
         14 . The apparatus of  claim 10 , wherein the first sensor and the second sensor are pressure sensors. 
     
     
         15 . A computer-readable medium having stored thereon instructions that when read by a processor enable the processor to perform a method, the method comprising:
 estimating a phase difference between a first signal provided by a first sensor and a second signal provided by a second sensor when the first sensor and the second sensor are deployed circumferentially apart on a downhole device in a well; and   estimating an orientation of the downhole device using the estimated phase difference.   
     
     
         16 . The computer-readable medium of  claim 15 , wherein estimating the phase difference further comprises applying a correction for a run-in of the downhole device. 
     
     
         17 . The computer-readable medium of  claim 16 , wherein applying the correction comprises using a well deviation from vertical, a measured depth, a run-in rate and a fluid density of a fluid in the well. 
     
     
         18 . The computer-readable medium of  claim 15 , wherein estimating the phase difference comprises at least one of: (i) applying a Short Term Fourier Transform; and (ii) estimating a quadrature signal of the phase difference between the first signal and the second signal. 
     
     
         19 . The computer-readable medium of  claim 15 , wherein the first signal and the second signal are pressure signals relating to pressure in the well. 
     
     
         20 . An apparatus for use in a well, comprising:
 a tool configured to be conveyed in the well, the tool including a first sensor and a second sensor disposed circumferentially spaced from each other, each sensor configured to provide measurements relating to a downhole parameter; and   a processor configured to:
 (i) estimate a phase difference between the measurements of the first sensor and the second sensor, and 
 (ii) estimate the orientation of the downhole device using the estimated phase difference.